Pave

men

t & M

ater

ials

Tec

hnol

ogy

1

Pavement Smoothness and IRI Ride Specifications

North Central Asphalt User Producer Group (NCGUPG)

Annual Meeting February 19 -20, 2014

Keeping America Moving

Pave

men

t & M

ater

ials

Tec

hnol

ogy

3

Pavement Surface Characteristics

Pave

men

t & M

ater

ials

Tec

hnol

ogy

4

Key Areas for SC program • Friction / Texture • Rolling Resistance • Noise • Splash and Spray • Smoothness / Ride Quality

Pave

men

t & M

ater

ials

Tec

hnol

ogy

5

Outcome – focus on ride quality Smoothness (IRI), Possible National Performance

Measure Highlight team efforts in establishing national/AASHTO

standards in pavement smoothness – need these for pavement condition performance measures.

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Benefits of Smooth Pavements

• Satisfied road users

• Decrease in fuel consumption and vehicle maintenance costs

• Pavements that are built smoother remain smoother over time and provide a longer service life

• Dynamic loadings are lower on smooth pavements

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Information on Ride Specs

www.smoothpavements.com

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Profilograph

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Profilograph Response

0

0.5

1.0

1.5

2.0Gain

Wavelength (ft)1000100101

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Representative Vehicle

• How many people drive a vehicle with a 25 foot wheelbase?

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Who said this? • No claim is made that the roughness or

riding quality of a pavement is directly or completely reflected by the profile index.

• It should again be emphasized that strictly speaking, the devices reported herein do not furnish a direct index to “riding qualities”.

– California Highways and Public Works, Vol. 39 March-April Nos. 3-4, “Profilograph-2” pg 54

• Francis N. Hveem, 1960 (inventor of the California Profilograph)

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Percent Within Limits: PWL Ride Data • Efficiently captures mean and standard deviation

in one quality measure

X 3s 2s 1s -3s -2s -1s

X - mean s - standard deviation

Pave

men

t & M

ater

ials

Tec

hnol

ogy

LSL

Single Specification PWL: Use of blanking bands

PWLL X

X Use of blanking bands of 0.1” and 0.2” cuts off the lower end of our normal distribution.

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Advantages of IRI • Reproducible, portable and stable with time

• General pavement condition indicator

• Describes roughness that causes vehicle

vibrations

Pave

men

t & M

ater

ials

Tec

hnol

ogy

IRI is highly correlated to: • Vertical passenger acceleration (Ride Quality)

• Tire Contact (vehicle control and safety)

• Output from Response Type Roughness

Measuring Systems

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Properties of IRI Analysis • IRI computed using quarter car model

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Computation of IRI

• Need longitudinal profile containing information relevant to ride

• Computation of IRI performed by a computer program as specified in ASTM Standard E1926

• Parameters of quarter car (e.g., spring stiffness, etc.) referred to as “Golden Car” parameters

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Response of IRI to Wavelengths

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Inertial Profiler Changes

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Potential Reference Devices

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Overview TPF 5(063)

FHWA is lead agency with 22 participating State Highway Agencies (SHA’s)

• FHWA Office of Pavement Technology (HIPT)

• $1.8 Million 12 Year Study • FHWA Long Term Pavement Performance

(LTPP) • FHWA Federal Lands

Pave

men

t & M

ater

ials

Tec

hnol

ogy

– Ohio – Louisiana – Kentucky – California – Colorado – Florida – Georgia – Kansas – Mississippi – New Jersey – Nevada

21 February, 2014

Participating State Agencies (22)

– New York – North Dakota – South Dakota – Illinois – North Carolina – Maryland – Oklahoma – Connecticut – Texas – Wisconsin – Pennsylvania

Pave

men

t & M

ater

ials

Tec

hnol

ogy

TPF 5(063) Priorities

1. Build Reference Profile Device 2. Critical Requirements - complete 3. Bumpfinder Software - complete 4. Certification/Validation Sites 5. Evaluating Upper Limits of Single

Accelerometer – Phase I complete 6. Emerging Technology that Enhances

Profile Measurement 7. Support RPUG

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Progress on TPF 5(063) Priorities

1. Build a Reference Profile Device (ongoing): Two parts –

i. Benchmark Testing – UMTRI ii. Reference Devices – New round of evaluations

May 2013 2. Critical Requirements (completed): UMTRI;

final report on pooled fund study website – “Critical Profile Accuracy Requirements”

Pave

men

t & M

ater

ials

Tec

hnol

ogy

TPF 5(063) Priorities - continued

3. ProVAL Software: The Transtec Group, Inc. – www.roadprofile.com

• ProVAL 3.3 released in December 2011 – Includes Automated Faulting Module

(AFM) • ProVAL 3.4 released Dec. 2012 • Multiple workshops – 10 annually

– Scheduling has started for FY13

Pave

men

t & M

ater

ials

Tec

hnol

ogy

TPF 5(063) Priorities continued

4. Certification/Validation Site i. Study under discussion with FHWA

5. Evaluating Upper Limits of Single Accelerometer

i. Phase I: Starodub, Inc. – complete ii. Phase II: On hold for publication

6. Emerging Technology that Enhances Profile Measurement

i. Urban IRI measurement – FHWA Federal Lands Study

ii. Urban and low speed profile indices – NCHRP 10-93

Pave

men

t & M

ater

ials

Tec

hnol

ogy

FHWA Toolkit • Smoothness

– ProVAL software (www.roadprofile.com) & workshops (10 per year)

– ASTM E2560-07: Standard Specification for Data Format for Pavement Profile

– NHI 131100 “Pavement Smoothness” – AASHTO Ride Quality Standards

Implementation Contract – Assist SHAs • M328 Equipment Specification • R54 Accepting Ride Quality using an inertial

profiler • R56 Certification of Inertial Profilers • R57 Operation of Inertial Profilers

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Inertial Profilers – Getting Better

Pave

men

t & M

ater

ials

Tec

hnol

ogy

ProVAL 3.4 software & workshops

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Frequently Asked Questions • Who does the testing, and if not the owner then how do

you certify machine and operator? – Best Practice: SHA for QA & contractor for QC

• NH uses average of three runs. TN uses average of five runs – SHA certify profilograph and inertial profiler equipment &

operators: set up a course & conduct annual equipment certification. FHWA assistance available.

– SHA conduct QA tests on contractor data • When is the testing done (daily, once paving complete,

or after open to traffic)? – QC as soon as possible to monitor – QA once paving complete

• If not tested generally the day after paving do you know how much difference there is by the time the pavement is opened to traffic?

– Unsure of studies related to this 32

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Frequently Asked Questions • What equipment/laser setup are you using for concrete?

– AASHTO standards recognize limits of single point lasers. Recommend using line laser that averages across its range

• What are the IRI numbers associated with

acceptance/incentives? And are they the same for asphalt? – Set by individual SHAs. MS uses same for both ACC & PCC. MN

uses combined spec with different thresholds. • http://www.dot.state.mn.us/materials/smoothnessdocs/2399_2-6-13.pdf

• What bump threshold number do you use for concrete and

is it the same as asphalt? – Set by each SHA, typically 0.3 inch for either pavement type

• What do you base your Incentive payments on (set amount per tenth mile or % of a bid price)?

– Set by each SHA, many use set amount per tenth mile 33

Pave

men

t & M

ater

ials

Tec

hnol

ogy

MnDOT 2013 Combined Spec HMA

34

Table 2399-4 Smoothness Pay Adjustments and Corrective Work for Bituminous

Pavements

Equation Smoothness in/mi [m/km]

Pay Adjustment $/0.1 mi [0.16 km]

HMA-A

< 30.0 [0.47]

400.00

30.0 – 75.0 [0.47 – 1.18]

850.00 − 15.000 × Smoothness [850.00 − 957.450 × Smoothness]

> 75.0 [1.18]

Corrective Work to ≤ 56.7 in/mi [0.89 m/km]

HMA-B

< 33.0 [0.52]

270.00

33.0 – 85.0 [0.52 – 1.34]

600.00 − 10.000 × Smoothness [600.00 − 638.950 × Smoothness]

> 85.0 [1.34]

Corrective Work to ≤ 60.0 in/mi [0.94 m/km]

HMA-C

< 36.0 [0.57]

180.00

36.0 – 95.0 [0.57 – 1.50]

414.00 − 6.500 x Smoothness [414.00 − 410.500 x Smoothness]

> 95.0 [1.50]

Corrective Work to ≤ 63.7 in/mi [1.01 m/km]

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Frequently Asked Questions • Do you use localized roughness in the IRI

specification, if so what are the parameters for PCCP? – Set by SHA and varies: MnDOT uses a continuously

reported IRI at 125 in/mi for both pavement types • What smoothness checks do you use for mid-speed

urban areas (40 to 50 mph) and how do you accomplish it? – Most agencies use ride indices (IRI or PI) for roadways

with speeds > 45 mph • If you have an IRI spec, do you still use a PI spec

(California Profilograph) in any locations? – Generally not, but some use straightedge for localized

roughness

35

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Frequently Asked Questions • Use ProVAL or the value the equipment software

provides? – Most agencies are specifying ProVAL

• Are there any additional deducts, besides grinding, to meet a minimum IRI? – Some agencies will remove and replace at high values

• If ground, can the section be re-profiled to attain a smoothness bonus? – Again varies by agency, some allow others do not

• Does your state use a combined specification for both concrete and asphalt, if so do you use the same equations/IRI specs for both pavement types?

– Set by each SHA & varies, MnDOT uses 30 in/mi for new ACC and 50 in/mi for PCC

36

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Frequently Asked Questions • Does your state require equipment and/or operator

certification? Yearly, every x years? – If using contractor data, equipment every year and operator

certification can vary from 3 to 5 years. MnDOT uses online training for operators.

• http://www.dot.state.mn.us/onlinelearning/mrr/pavementsmoothness/ • Do you require ProVAL?

– Most agencies do when using IRI and can be used for PrI when collected with inertial profiler but ProVAL cannot be used for data collected by profilograph.

• Do you see an influence on type of pavement texture? – Coarse textures i.e. chip seals, tining, OPFC, challenge single

point lasers. Line lasers provide viable alternative. • Some states set their specs so tight they end up having the

entire pavement ground – how do they handle that? How do you minimize grinding on the finished project?

– Specs can be changed, but most tighten specs after contractors learn how to build smooth roads.

– Good construction practices that include daily evaluations of finished product. 37

Pave

men

t & M

ater

ials

Tec

hnol

ogy

Contact Info

Robert Orthmeyer, FHWA Resource Center Robert.Orthmeyer@dot.gov (708) 283-3533